Can I use interconnect cables as power cables?

[Audiofire]

You can use anything as a power cable - once.

The most correct answer technically speaking...

Keep in mind insulation can even catch on fire if it is not certified/constructed for AC mains voltage. So I don't think there is any reason to risk burning a building down, or human beings for that matter. The certifications in use are IEC 60331, IEC 60332, IEC 60754 and IEC 61034.

The cables certified for indoors in the European Union are H03VV-F (low voltage) and H05VV-F (high voltage) that have PVC insulation. There is H07RN-F for outdoors that has rubber insulation (it can also smell of rubber that will make people want to keep it out of their rooms).

 

[dshreter]

Of course. You can also pour orange juice in your coffee

 

[Audiofire]

If your audio product has an earth connection on the power cable, it is likely there to protect you. It can be identified from having 3 prongs instead of 2. If you really care, it is highly recommended to read the following (maybe the whole source):
"Consumer audio and video equipment electrocuted 9 people in the U.S. in 1997, the latest year for which statistics are available. That same year, this equipment caused 1,900 residential fires which resulted in 110 civilian injuries, 20 deaths, and over $30 million in property losses. [6] [7] The resistance of dry human skin is high enough to safely allow lightly touching a live 120-volt conductor, but normal skin moisture allows more current to flow as does increased contact area and pressure. It is current that determines severity of electric shock. At 1 mA or less, it’s simply an unpleasant tingle. But at about 10 mA, involuntary muscle contractions can result in a “death grip” - or suffocation if the current flows through the chest. Currents of 50 to 100 mA through the chest usually induce ventricular fibrillation that leads to death. Always have a healthy respect for electricity!"

Source:
Understanding, Finding, & Eliminating Ground Loops in Audio & Video Systems by Bill Whitlock

 

[Ingenieur]

Yes
But don't

You can buy a Triplp Lire 14 AWG UL listed cord on Amazon for $15.
DIY connectors would cost more.
16 AWG should be fine if runs <10 feet.

Amazon.com: Tripp Lite Desktop Computer Power Cord, Right-Angle 5-15P to C13 - Heavy Duty, 15A, 125V, 14 AWG, 6 ft, Black (P007-006-15D) : Electronics

Amazon.com: Tripp Lite Desktop Computer Power Cord, Right-Angle 5-15P to C13 - Heavy Duty, 15A, 125V, 14 AWG, 6 ft, Black (P007-006-15D) : Electronics

www.amazon.com

 

[Audiofire]

You can buy a Triplp Lire 14 AWG UL listed cord on Amazon for $15.
DIY connectors would cost more.
16 AWG should be fine if runs <10 feet.

That is only for 120 volts due to Ohm's law.
So America generally uses 16 gauge instead of the 18 gauge minimum in Europe.
The original poster did not even specify where the user is from, so we are working on insufficient data here.

Edit: That is 0.75 mm², so about 18.5 gauge minimum in Denmark for power cables.

 

[Ingenieur]

That is only for 120 volts due to Ohm's law.
So America generally uses 16 gauge instead of the 18 gauge minimum in Europe.
The original poster did not even specify where the user is from, so we are working on insufficient data here.

The plugs are rated for 125 V due to configuration.
The cable is 300 V

Assume average power is 200 W
Peak is 400 W
Estimate VA at 800
At 120 v ~ 6.7 A
At 240 ~ 3.3 A
Ampacity of cable is 15 A
If he's in Europe (or many other places) the plugs won't fit.

What is this " Ohm's Law " you speak of?

 

[Rja4000]

Does it violate the electrical code because the intention of sales was as an interconnect and not a power cable,

The power cables have to be build according to standards, and to be labelled as such.

Standards cover more than the conductor size and material.
They also cover isolation material and efficiency, mechanical properties, fire resistance,...

Forget this idea.

 

[Ingenieur]

The US NEC only defines construction of the system. Not what is plugged into it.
UL (and other listing agencies) do that.

I can't think of any codes this would violate?
Your insurer won't like it.

 

[Audiofire]

What is this " Ohm's Law " you speak of?

"Watt's Law states that: Power (in Watts) = Voltage (in Volts) x Current (in Amps) P = V I Combining with Ohm's law we get two other useful forms: P = V*V / R and P = I*I*R"

Source:

Introduction to Electronics - CCRMA Wiki

ccrma.stanford.edu

There is both Watt's law and Ohm's law, but the original post in the thread implies a risk of combustion.

 

[Chrispy]

My first thought is why in hell would you want to? But without details...

 

[EdTice]

The plugs are rated for 125 V due to configuration.
The cable is 300 V

Assume average power is 200 W
Peak is 400 W
Estimate VA at 800
At 120 v ~ 6.7 A
At 240 ~ 3.3 A
Ampacity of cable is 15 A
If he's in Europe (or many other places) the plugs won't fit.

What is this " Ohm's Law " you speak of?

I am not qualified to comment on electrical safety codes and requirements and make no attempt to do so here. If peak amplifier power is 400W, average power will be about 4W for any live material and an 40W for compressed music played loud enough for the amp to be inaudibly clipping. You can run a 5000W amplifier on a 1500W circuit and will not have problems. Even with a 6dB crest factor this would not overload the circuit. I am in no way suggesting that you use cords that are not appropriately rated for the device that you are powering. Power cables are incredibly cheap and trying to save a dollar (or euro) or two on them is unwise.

Power amplifiers for music are a special beast in that, their average power use is always much less (unless you are playing a 3dB sin wave to test the equipment) than the rated power.

I can't remember if the (very conservative) safety engineering standard for live performances is 8x or 12x. I use 10x to estimate since the math is easier.

We care about this because severely over-estimating power requirements can also be a safety issue. Having a 60amp secondary circuit to your theater room rather than just running off of the existing 15A socket might actually reduce safety rather than increasing it. (Although still way better than doing something outside of safety codes)

 

[Ingenieur]

I am not qualified to comment on electrical safety codes and requirements and make no attempt to do so here. If peak amplifier power is 400W, average power will be about 4W for any live material and an 40W for compressed music played loud enough for the amp to be inaudibly clipping. You can run a 5000W amplifier on a 1500W circuit and will not have problems. Even with a 6dB crest factor this would not overload the circuit. I am in no way suggesting that you use cords that are not appropriately rated for the device that you are powering. Power cables are incredibly cheap and trying to save a dollar (or euro) or two on them is unwise.

Power amplifiers for music are a special beast in that, their average power use is always much less (unless you are playing a 3dB sin wave to test the equipment) than the rated power.

I can't remember if the (very conservative) safety engineering standard for live performances is 8x or 12x. I use 10x to estimate since the math is easier.

We care about this because severely over-estimating power requirements can also be a safety issue. Having a 60amp secondary circuit to your theater room rather than just running off of the existing 15A socket might actually reduce safety rather than increasing it. (Although still way better than doing something outside of safety codes)

The amp is rated 200 W, so that is what te cord should be sized for.
The 200 W is based on RMS values
V and I peak / sqrt2
P = Vp/sqrt2 x zip/sqrt2 = Vp Ip / 2
An 'average' value
So peak is 2 x average in this case
Bathe load is reactive so an estimate of power factor + eff is ~0.5
Peak VA = 2 x 200 / 0.5 = 800 VA

But to your point. Yes, draw will typically be fractions of an amp and likely more that 5 under transient conditions.

 

[EdTice]

The amp is rated 200 W, so that is what te cord should be sized for.
The 200 W is based on RMS values
V and I peak / sqrt2
P = Vp/sqrt2 x zip/sqrt2 = Vp Ip / 2
An 'average' value
So peak is 2 x average in this case
Bathe load is reactive so an estimate of power factor + eff is ~0.5
Peak VA = 2 x 200 / 0.5 = 800 VA

But to your point. Yes, draw will typically be fractions of an amp and likely more that 5 under transient conditions.

I haven't had to do this in a long time, so again, I don't want to encourage anybody to be unsafe with electricity. I believe the rule is that you can use a factor of 8x or 12x (whichever it is) as long as there is an appropriate breaker or fuse to prevent a fire should you actually go over. You would be able to use a cord rated as low as ~20 watts on a 200 watt amp if and only if there were a fuse/breaker between the amp and mains that would trip at nominal 20 watts. I say nominal because those disconnects all have a slope. Otherwise you would need a cord rated for 200watts.

You are within safety specs running up to ~12kwatts on a 15amp circuit (120V North America) with just the breaker (no intermediate disconnects). It will be safe because the breaker is there. It will work because of the slope of the breaker (drawing the full 12kwatts for a millisecond won't trip the breaker).

Note that the fuses in the amps don't count. Because they are "closer" to the amp than the power source.

If you could find say a power strip that connected to mains with a 15amp breaker *and* 0.2 amp fuses on each outlet, you would be within code to use a lower rated power cord (since the fuses are closer to mains than the load). Unfortunately I could not find such a device probably because it's cheaper and easier to buy IEC cords!

I didn't bring this up to encourage people to do silly things especially when power cords are so cheap.

If somebody had say 2xSVS SB2000 with 1100watts peak power and a Behringer A800 (800 watts) they might think that they need multiple 15 amp circuits and, in the worst case, could end up paying the electrician for additional drops and achieve nothing but introducing ground loop noise!

As far as I know (and please correct me if I'm wrong as we really do want to avoid unsafe situations), that whole 3000 watt load can be put into a single 15amp (US 120volt) circuit along with the TV and AVR with no safety issue and no risk of tripping the breaker. However, if you put it on the same circuit as the microwave, that's a different story.

These things used to matter in pro audio but not home theater or hifi. Now we suddenly have stereo amplifiers that can put out 600wpc (Nord 28) and suddenly we need to manage power as if we are setting up pro audio.

 

[Ingenieur]

I haven't had to do this in a long time, so again, I don't want to encourage anybody to be unsafe with electricity. I believe the rule is that you can use a factor of 8x or 12x (whichever it is) as long as there is an appropriate breaker or fuse to prevent a fire should you actually go over. You would be able to use a cord rated as low as ~20 watts on a 200 watt amp if and only if there were a fuse/breaker between the amp and mains that would trip at nominal 20 watts. I say nominal because those disconnects all have a slope. Otherwise you would need a cord rated for 200watts.

You are within safety specs running up to ~12kwatts on a 15amp circuit (120V North America) with just the breaker (no intermediate disconnects). It will be safe because the breaker is there. It will work because of the slope of the breaker (drawing the full 12kwatts for a millisecond won't trip the breaker).

Note that the fuses in the amps don't count. Because they are "closer" to the amp than the power source.

If you could find say a power strip that connected to mains with a 15amp breaker *and* 0.2 amp fuses on each outlet, you would be within code to use a lower rated power cord (since the fuses are closer to mains than the load). Unfortunately I could not find such a device probably because it's cheaper and easier to buy IEC cords!

I didn't bring this up to encourage people to do silly things especially when power cords are so cheap.

If somebody had say 2xSVS SB2000 with 1100watts peak power and a Behringer A800 (800 watts) they might think that they need multiple 15 amp circuits and, in the worst case, could end up paying the electrician for additional drops and achieve nothing but introducing ground loop noise!

As far as I know (and please correct me if I'm wrong as we really do want to avoid unsafe situations), that whole 3000 watt load can be put into a single 15amp (US 120volt) circuit along with the TV and AVR with no safety issue and no risk of tripping the breaker. However, if you put it on the same circuit as the microwave, that's a different story.

These things used to matter in pro audio but not home theater or hifi. Now we suddenly have stereo amplifiers that can put out 600wpc (Nord 28) and suddenly we need to manage power as if we are setting up pro audio.

The rule of thumb (and some Codes)
Size conductor for 125% of max load
Size equipment for 80% of conductor
Circuit breaker = to conductor or next size up
There are variations for continuous load, duty factor, motors, etc.

Example:
50 A load
125% ~62.5 A
Use 6 AWG 65 A conductor
iirc correctly 70 A(?), maybe 65 ?
Just looked, 60 then 70, no 65

 

[antcollinet]

Wire size is not supposed to be limited by the power rating of the equipment, but by the supply side protection (fuse or circuit breaker). The intent is that the power cord can withstand whatever fault current the protection will allow - without the cord catching fire.

In the UK we have fuses in the plug to help with this since our main power circuits have 32A protection devices. Not sure about USA - perhaps the fuse is in the equipment, or the circuits are protected at a lower current level.

 

[EdTice]

Wire size is not supposed to be limited by the power rating of the equipment, but by the supply side protection (fuse or circuit breaker). The intent is that the power cord can withstand whatever fault current the protection will allow - without the cord catching fire.

In the UK we have fuses in the plug to help with this since our main power circuits have 32A protection devices. Not sure about USA - perhaps the fuse is in the equipment, or the circuits are protected at a lower current level.

One would think not. Here in the US, though, one can get away with that a bit. But I don't know the rules/circumstances. In some scenarios, the fuse can be at the *device* end of the cord. One obvious example is lamp cords where the "fuse" is the bulb itself. But this isn't true for Christmas lights where one bulb out doesn't bring down the circuit. In that case, you have to have a separate fused. Many computers, TVs, monitors, and even audio equipment (occasionally) ship with 18awg power cords which aren't fused at the plug end. Most pro audio equipment that has a fuse at the equipment end. But I've never seen it at the plug end (even when the equipment uses two-conductor wire).

In the US, most circuits are protected at 15amps. But most of our equipment would catch fire at 1amp! The reason most of us don't worry about this stuff is that if you buy products with safety ratings (as Amir always encourages), you can just use it (as long as you don't get "ideas"). Now that we see things like 600wpc stereo HiFi amplifiers, one has to start thinking not about what happens between the wall and the device but how the 15A circuit is suddenly "oversubscribed." Again good news is that, unless you start doing things like making your own cords, breakers and fuses have gotten good enough that not too many homes burn down from electrical fires.

 

[egellings]

My question is, why on earth do you want to use a small signal cable to carry a lot of power, when good 'ol power cords have been successfully doing that for so long?

 

[Audiofire]

In the UK we have fuses in the plug to help with this since our main power circuits have 32A protection devices.

Wow, we have fuses at the circuit breaker that matches the amperage of the house wiring. Or lower. 10 amp fuse at the main power circuit for 1,5 mm² house wiring is the minimum (2300 W/230 V=10 A).

My question is, why on earth do you want to use a small signal cable to carry a lot of power, when good 'ol power cords have been successfully doing that for so long?

It comes down to a misunderstanding of the difference between signal cables and power cable, but the original poster already made it clear right in the beginning of the thread that the advice is understood.

 

[antcollinet]

Wow, we have fuses at the circuit breaker that matches the amperage of the house wiring. Or lower. 10 amp fuse at the main power circuit for 1,5 mm² house wiring is the minimum (2300 W/230 V=10 A).

Our 32 amp circuits are 2.5mmsq - but they are also (mainly) ring circuits, so effectively doubled.

 

[Audiofire]

Wow, we have fuses at the circuit breaker that matches the amperage of the house wiring. Or lower. 10 amp fuse at the main power circuit for 1,5 mm² house wiring is the minimum (2300 W/230 V=10 A).

That is to say 10 or 13 amp breakers are quite normal in Denmark, but fuses are most likely still used.

10 AWG: check
Shielded: check
Pretty: check
Cheap: check
Electrons love it: check
Power Cable on Amazon

Copper shielding is the worst dielectric, and power cables even have far greater electromagnetic fields than some overpriced, wrongly shielded, massively oversized, unnecessary signal cable (the adjectives that are missing on a lot of high-end cables)...